Subsurface Model Accuracy via Seismic-While-Drilling Full Waveform Inversion
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Solution Overview
Problem
Current subsurface drilling operations face challenges due to incomplete and uneven imaging of the subsurface, resulting from non-uniform seismic ray path coverage and logistical constraints, which can lead to costly delays and damage to drilling equipment.
Innovation Solution
A system and method that utilizes successive full waveform inversions of surface seismic data and seismic-while-drilling data to generate a more accurate subsurface model, incorporating drillbit source signature estimation and top-drive measurements, to guide drilling operations and improve well placement and reservoir models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface sensors are used to image the subsurface, then seismic data can be obtained, but the ray path coverage becomes non-uniform and resolution is reduced
Solution Approach 1:
The patent transitions from surface-only seismic acquisition to a multi-dimensional approach by deploying sensors both at the surface and within boreholes. This dimensional expansion of sensor placement enables ray paths to penetrate and sample shadow zones that are inaccessible to surface-only methods, thereby improving subsurface imaging resolution and uniformity.
Solution Approach 2:
The patent implements a nested sensor deployment strategy where borehole sensors are positioned within the subsurface volume, effectively nesting the measurement system inside the target region. This nested configuration allows internal sampling of seismic waves, providing complementary ray paths that penetrate shadow zones and improve overall imaging coverage.
2Measurement precision
If dense seismic source and receiver deployment is implemented, then ray path coverage improves, but logistical and economic constraints are violated
Solution Approach 1:
The patent segments the seismic acquisition system into surface and borehole components. This segmentation allows the complex problem of dense sampling to be divided into manageable parts: surface sensors provide broad coverage while borehole sensors provide targeted internal sampling. The segmented approach achieves improved ray path coverage without requiring uniformly dense deployment throughout the entire survey area.
Solution Approach 2:
The patent applies local quality by concentrating sensor resources in specific strategic locations (boreholes) where they provide maximum value for sampling shadow zones. Rather than uniformly dense deployment, the system places sensors locally where needed to improve specific regions of subsurface imaging, optimizing resource allocation while achieving enhanced resolution.
3Measurement precision
If conventional seismic inversion is used, then subsurface models can be generated, but accuracy is reduced in shadow zones
Solution Approach 1:
The patent introduces borehole sensors as an intermediary measurement system that bridges the gap in shadow zone coverage. These intermediate sensors are positioned to receive seismic energy that would otherwise be blocked or weakly sampled by surface-only acquisition, providing direct measurements from within the shadow zones and enabling more accurate subsurface modeling in previously inaccessible regions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a high-resolution subsurface image, reducing drilling risks and improving efficiency by enhancing the accuracy of subsurface understanding and enabling better decision-making during drilling operations.
Implementation Method 1
surface sensor that is recording the elastic energy radiated from surface seismic source
Implementation Method 2
subsurface sensor that is recording the elastic energy radiated from the interaction of the drillbit with the rock while drilling
Implementation Method 3
FWI is a computational framework that transforms the recorded seismic data to the high-resolution rock properties of the subsurface
Data Source
AI summary
System and method for guiding a drill using a subsurface model generated by successive full waveform inversions (FWI) on surface data and seismic-while-drilling (SWD) data. A server receives surface data from at least one surface sensor that records elastic energy radiated from surface seismic source and SWD data from at least one surface or at least one subsurface crosswell sensor (i.e., deployed in a nearby well). The server also receives top-drive measurements. A drillbit source signature estimation is performed, on the SWD data, by the server by blind deconvolution or by using drill string modeling and top-drive measurements. The server then performs FWI on the surface data by using the background subsurface velocity obtained by kinematic analysis of surface seismic data, to obtain an updated approximation of the subsurface velocity. The new approximation along with the drillbit source signature is then used when performing FWI on the SWD data.